The prior art 1 is Japanese patent application publication No. 2001-243807 published on Jul. 9, 2001 discloses “LED ELECTRIC BULB” that PROBLEM TO BE SOLVED: To provide a LED electric bulb capable of obtaining a white light of large luminous flux and a wide illumination range with a simple structure and distributing luminous intensity in various light distributing patterns, and compatible with a conventional incandescent lamp. SOLUTION: This electric bulb is provided with a base 1 on one end, a bugle shaped member 2 expanding like a bugle toward an opening part on the other end, a translucent cover 5 attached to an opening part of the bugle shaped member 2 and having a fluorescent material layer on an inner surface of the same, a substrate 3 provided inside of a nearly spherical body 7 formed by the bugle shaped member 2 and the translucent cover 5, and LED elements 4 mounted on an outer surface of the substrate 3 facing the translucent cover 5. (See “Patent Abstract Japan” Publication No. 2001-243807 English version.)
The prior art 2 is Japanese patent application publication No. 2006-156187 published on May 6, 2006 discloses “LED LIGHT SOURCE DEVICE AND LED ELECTRIC BULB” that PROBLEM TO BE SOLVED: To promote life-prolongation of a phosphor and a light emitting diode element, while enabling the brightness of light to become approximately uniform of which the wavelength is converted with a wavelength conversion cover. SOLUTION: This is provided with an LED light emitting diode part 6 having a plurality of light emitting diode elements 12 which are arranged so as to have a plane surface and radiate near-ultraviolet rays or blue rays, and the wavelength conversion cover 9 which has a planar part 16 opposing to the light emitting diode elements 12 in a separated position at a prescribed distance from the face where the light emitting diode elements 12 are arranged, and in which a phosphor 15 is installed that carries out the wavelength conversion of the light radiated from the light emitting diode elements 12. (See “Patent Abstract Japan” Publication No. 2006-156187 English version.)
In the prior art 1, since a phosphor layer is only formed on the inner surface of the semi-spherical transparent cover (globe), a formation area of the phosphor layer is limited so that this LED lamp is not sufficient in a brightness, luminance and in a light distribution angle for use in a replacement of conventional incandescent light bulb.
In the prior art 2, since the wavelength conversion planer cover including the phosphor opposing the LED element is located in an inner space of the semi-spherical globe, a formation area of the phosphor layer is limited similarly to the prior art 1 so that this LED lamp is not sufficient in a brightness, luminance and in a light distribution angle for use in a replacement of conventional incandescent light bulb.